Complete genome sequence of Salinigranum rubrum GX10T, an extremely halophilic archaeon isolated from a marine solar saltern
Since the first genome of a halophilic archaeon was sequenced in 2000, microbes inhabiting hypersaline environments have been investigated largely based on genomic characteristics. Salinigranum rubrum GX10T, the type species of the genus Salinigranum belonging to the euryarchaeal family Haloferacaceae, was isolated from the brine of Gangxi marine solar saltern near Weihai, China. Similar with most members of the class Halobacteria, S. rubrum GX10T is an extreme halophile requiring at least 1.5?M NaCl for growth and 3.1?M NaCl for optimum growth. We sequenced and annotated the complete genome of S. rubrum GX10T, which was found to be 4,973,118?bp and comprise one chromosome and five plasmids. A total of 4966 protein coding genes, 47 tRNA genes and 6 rRNA genes were obtained. The isoelectric point distribution for the predict proteins was observed with an acidic peak, which reflected the adaption of S. rubrum GX10T to the halophilic environment. Genes related to potassium uptake, sodium efflux as well as compatible-solute biosynthesis and transport were identified, which were responsible for the resistance to osmotic stress. Genes related to heavy metal resistance, CRISPR-Cas system and light transform system were also detected. This study reports the first genome in the genus Salinigranum and provides a basis for understanding resistance strategies to harsh environment at the genomic level.